It's also entirely possible that Amazon does handle verification, but they have set their operator metrics so high, the operators are forced to speed through the process.

We see this in other areas of logistics as well - delivery people sprinting and tossing packages because they can't spend more then X seconds per stop.

I've spent a lot of time in distribution centers over the last decade. The vast majority of people just want to do a good job, even if the job isn't a good one.